Sean, I do not know at what point in time or at what temperature meat or other food product will spoil in a freezer or when food looses its nutritional value. Having owned separate home freezers for fifty years I now something about frozen foods and how time effects their taste. These freezers were operated in a temperature range of +4 to +15 degrees F. Living in the country I purchased a hanging quarter or half a beef cut, rapped, and quick frozen. Beef stored at my freezer temperatures were generally good tasting for three to four months.
My sailboat has a small freezer with two opposing +10 degree holding plates connected to both an engine
driven system and a air-cooled Adler Barbour BD 2.5 condensing unit. When running the refrigeration
system off the engine
drive the freezer temperature drops to zero then rises to a high of 20 degrees if the engine is stopped for 24 hours. Running the refrigerator
only from the 12 volt AB with the thermostat set to zero and compressor
cycling it will maintain a ten degree temperature differential. I built my first holding plate in the 1950’s to use as a ground air conditioning
unit for aircraft and another 200+ plates for boat
refrigerators in the last twenty years.
I do not think that you will find a conventional holding plate system in a boat
that will maintain a zero degree F. box temperature as recommended by the government
do to the temperature swing when the compressor
is not running. A system with a compressor that can run a few minutes every hour can maintain the box at zero and below even when a holding plate’s solution is set to freeze at +10 degrees or even +26 degrees F.
Most people do not understand the history
and function of a holding plate, they are not better than other types of evaporators they are energy storage
devices. In some applications a holding plate is less efficient than a conventional evaporator if it is so small it lacks at ability to dissipate the capacity of its refrigeration systems compressor. In the 1940’s and maybe earlier holding plates were used on city delivery
trucks to store energy because trucks did not have on-board compressors back then. Capturing and storing excess energy is the only purpose for holding plates in a boats refrigerator and not because they are more efficient. With the improvements in DC power systems on boats and the new generation of more efficient compressors there is little need today for holding plates. There are some companies selling small 12 volt systems with small holding plates that I believe is only a sales gimmick.
Sean, Technicold has a good system and there are boats that have large refrigeration needs that can not be achived with evaporator type systems which require continuous power all day.